Foundry pattern craftsmen require many years of careful training, and must exercise a high degree of skill. The accuracy of the finished casting is dependent entirely on the accuracy of the pattern itself, and consequently the work cannot be undertaken by unskilled trades people. The training of such patternmakers in fact represents such a considerable investment that few companies are willing to undertake it. In addition, it is becoming difficult to find new recruits to enter the trade.
In addition, since the trade or craft is highly skilled, and is relatively slow, the cost of foundry patterns is becoming excessive.
Usually, the patterns are made of solid wood, usually sections of wood joined together, so as to provide the desired exterior topology of the finished casting.
There are many other instances when it is desired to reproduce a surface or topology using electronic data information. For example, topology models may be made from topographical map information, or from EDP information derived from stereo photographs, the information being used to make a three-dimensional topology model. Similarly, architectural drawings, or marine drawings may also be compiled as EDP information. In addition there are many manufacturing techniques and articles which should ideally be modelled prior to finalizing the design, but in many cases are not possible due to the difficulty of making satisfactory patterns or models at an economical price.
For all of these reasons it is, therefore, desirable to provide a machine capable of reproducing a predetermined topology, on the upper surface of a body. In particular, it is desirable that such a machine shall be capable of reproducing the three-dimensional topographical surface of an article, from a drawing of that article.
It is also desirable that such a machine should be capable of reproducing the topology of an article itself.